🌸 Benign Breast Disease
Breast pain, fibroadenoma, fibrocystic change, breast cysts, duct ectasia, periductal mastitis, intraductal papilloma, fat necrosis, gynaecomastia — MRCS high-yield.
Overview of Benign Breast Disease
The vast majority of breast lumps are benign. All require triple assessment to exclude malignancy — a benign diagnosis is never assumed from clinical examination alone. Understanding the key benign conditions, their typical presentations, and how they are managed is essential for the MRCS examination.
| Condition | Typical Age | Key Feature | Investigation | Management |
|---|---|---|---|---|
| Fibroadenoma | 15–35 years | Smooth, mobile, rubbery — “breast mouse” | USS ± core biopsy | Excise if >3 cm, symptomatic, or cosmetic concern |
| Breast cyst | 35–55 years (peri-menopausal) | Smooth, round, well-defined — may be tender; fluctuant if superficial | USS (anechoic = simple cyst); aspirate if symptomatic | USS-guided aspiration; re-image if bloody aspirate or lump persists |
| Fibrocystic change | 25–50 years | Diffuse nodularity; cyclical pain and tenderness; worse premenstrually | USS ± mammography; biopsy if focal area | Reassurance; evening primrose oil; analgesia; danazol for severe mastalgia |
| Intraductal papilloma | 30–50 years | Bloodstained or serous unilateral spontaneous nipple discharge from single duct; may have a small subareolar mass | USS; ductoscopy; duct excision (microdochectomy) | Microdochectomy (total duct excision if multiple ducts / older patient) |
| Duct ectasia | 40–60 years (peri/post-menopausal) | Thick green/brown/cheesy multiduct discharge; nipple retraction; subareolar mass | USS; mammography | Reassurance if asymptomatic; total duct excision if symptomatic or concerns persist |
| Periductal mastitis | 30–40 years; associated with smoking | Subareolar inflammation/abscess; nipple retraction; fistula to areola | USS; triple assessment | Antibiotics (anaerobic cover); incision and drainage; smoking cessation; Hadfield’s procedure (total duct excision) for recurrent disease |
| Fat necrosis | Any age; history of trauma or surgery | Hard, irregular, possibly skin-tethered lump — mimics carcinoma; oil cysts on mammogram (eggshell calcification) | Triple assessment; core biopsy to exclude malignancy | Reassurance once benign confirmed; excision if diagnostic doubt persists |
| Gynaecomastia | Neonatal, pubertal, elderly males | Subareolar breast tissue enlargement in males; usually bilateral and symmetric; tender | USS; hormonal screen; exclude malignancy | Treat underlying cause; danazol/tamoxifen; subcutaneous mastectomy for persistent cosmetic concern |
The ANDI Classification
ANDI (Aberrations of Normal Development and Involution) is the framework used to understand benign breast conditions. It proposes that most benign breast diseases represent aberrations of the normal physiological processes of the breast — development, cyclical change, and involution — rather than discrete disease processes:
- Development phase (15–25 years): Fibroadenoma (aberration of lobule development)
- Cyclical change phase (25–40 years): Cyclical mastalgia, fibrocystic change, cyclical nodularity
- Involution phase (35–55 years): Breast cysts, sclerosing adenosis, duct ectasia
ANDI replaces older confusing terms like “fibroadenosis” and “chronic mastitis” that implied inflammation. Most of these conditions require reassurance and explanation rather than treatment.